The data dictionary should not have any statistics on them and thus will use
rule as a rule so to speak.
If you have run stats on the data dictionary you coul dbe running into some
odd bugs.
-Original Message-
Sent: Tuesday, October 28, 2003 2:49 PM
To: Multiple recipients of list
By default it's set to
'choose' - but if try to use it for looking at locks (or most any ddl) it will
take forever to come back -you have to go to the options menu and pick
'rule' for optimzer modeon ddl queries.
[EMAIL PROTECTED] 10/28/2003 2:49:29 PM
does the data dictionary still use
does the data dictionary still use rule by support? any idea why toad would bother
slipping it in?
From: John Shaw [EMAIL PROTECTED]
Date: 2003/10/28 Tue PM 02:59:25 EST
To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED]
Subject: Re: ora-600 question
TOAD puts a hint in.
Hi!
Just for the record, in 9.2 some views such dba_extents use ordered and
use_nl hints, which force usage of CBO.
If you don't have statistics calculated nor optimizer_dynamic_sampling set
to at least 2, then you'll be using CBO with default statistics, which
usually are quite misleading.
If there're already hints like ordered and use_nl that tell Oracle how to join,
lack of statistics is less of a problem. In fact, you may need to use those two
hints in some queries against data dictionary even in pre-9i Oracle.
Yong Huang
--- Tanel Poder [EMAIL PROTECTED] wrote:
Hi!
Just
Depending on the query, in dba_extents example there are hints only in one
part of multi-part union all SQL, but nevertheless, good point :)
Tanel.
- Original Message -
To: Multiple recipients of list ORACLE-L [EMAIL PROTECTED]
Sent: Wednesday, October 29, 2003 1:04 AM
If there're
